Devices, methods and systems for establishing supplemental blood flow in the circulatory system

ABSTRACT

Devices, systems and methods for establishing a blood flow conduit between a chamber in a heart of a patient and a remote location. A blood inflow cannula having an outer surface and proximal and distal end portions. The distal end portion is configured for insertion into the chamber of the heart. First and second anchor elements have respective maximum width dimensions extending outwardly from the outer surface of the cannula. The first anchor element is positioned more distally than the second anchor element defining a tissue receiving space therebetween. The maximum width dimension of the first anchor element may be larger than the maximum width dimension of the second anchor element in use. The first anchor element is configured to be positioned inside the heart chamber and the second anchor element is configured to be positioned outside the heart chamber with heart tissue held in the tissue receiving space therebetween.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of patent application Ser. No.15/407,53, filed Jan. 17, 2017, which is a continuation of patentapplication Ser. No. 12/392,62, filed Feb. 25, 2009, now U.S. Pat. No.9,572,917, issued Feb. 21, 2017, which is a continuation ofPCT/US2007/076956, filed Aug. 28, 2007 (expired) which is related to andclaims priority to U.S. Provisional Patent Application Ser. No.60/823,971, filed Aug. 30, 2006, (expired) the entirety of which isincorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

n/a

TECHNICAL FIELD

This invention generally relates to medical devices and methods and,more particularly, to methods and devices for fluid coupling to theheart of a patient in systems for assisting blood circulation in apatient.

BACKGROUND

Various devices and methods have been utilized to conduct blood from theheart to assist with blood circulation in a patient. This is oftendesirable or necessary in cases where a patient is experiencingcongestive heart failure and a transplant organ has either not beenlocated, or the patient is not a suitable candidate for a transplant.The blood pumps are typically attached directly to the left ventricle ofthe heart, however, at least one blood pump system locates the pumpremotely, such as subcutaneously in the manner of a pacemaker. In thisregard, see U.S. Pat. No. 6,530,876, the disclosure of which is herebyfully incorporated by reference herein. In this situation or similarsituations, a cannula may be used to create an inflow conduit from theheart (an intra-thoracic location) to a pump located in a superficial(non-thoracic cavity) location, which may be the so-called “pacemakerpocket.” Of course, other remote locations are possible as alternatives.The pacemaker pocket is a location usually accessed by a surgicalincision generally parallel to and below the collarbone extending downtoward the breast, and over the pectoral muscle. Sometimes the pacemakerpocket is made below the muscle. The pump, to which the cannula isconnected, is intended to sit in the pectoral pocket, and is preferablybut not limited to the right side of the chest.

One area in need of improvement is the anchoring mechanism used tofluidly connect the inflow conduit or cannula to the heart. The cannulacan be connected and anchored to any chamber of the heart from which itis desired to conduct or conduit blood. One anchor point is the leftside of the heart, such as the left atrium. This is shown in U.S. Pat.No. 6,530,876. It would be desirable to ensure that this connection isas secure and leakage free as possible. In addition, the procedure formaking the connection should be as simple as possible under thecircumstances.

General cannula implantation methods known and usable in connection withthe present invention may involve many different approaches and severalof the representative approaches are described further below. Forexample, the cannula may be implanted by directly invading the thoraciccavity. Other surgical methods include so-called open heart surgery inwhich a median sternotomy is made to fully expose the heart within thethoracic cavity. Still other surgical methods include less invasivesurgical methods such as a thoracotomy, mini-thoracotomy, thoracoscopic,or any other less invasive approaches. Any of these surgical methods canbe used to implant the cannula in fluid communication with any desiredlocation of the heart as described herein.

Alternatively, a transluminal method of implanting the cannula may beused in which the thoracic cavity is not invaded directly, but ratherthe heart is accessed utilizing blood vessels naturally connecting intothe heart. Translumial methods include so-called transvenous delivery ofthe cannula to the left side of the heart via the right side of theheart to which the major veins and the more distal peripheral veinsprovide natural conduits through which the cannula can be delivered. Inthis approach, the cannula may more precisely be referred to as acatheter. Transluminal methods generally utilize indirect visualization,such as by means of contrast-dye enhanced fluoroscopy and/or ultrasonicimaging to navigate devices through the vessels of the body.

SUMMARY

Generally, and in one of many alternative aspects, the present inventionprovides a device for establishing a blood flow conduit between achamber in a heart of a patient and a remote location, such as alocation at which a blood pump resides away from the heart. In thisregard, the term “remote,” as used herein means away from the heart butis not limited to any particular distance from the heart. The devicecomprises an inflow cannula having an outer surface and proximal anddistal end portions (relative to a surgeon implanting the cannula). Thedistal end portion is configured for insertion into the chamber of theheart. First and second anchor elements having respective maximum widthdimensions extend outwardly from the outer surface of the inflow cannulaat its distal end portion. The first anchor element is positioned moredistally than the second anchor element and a tissue receiving space isdefined between the first and second anchor elements. The maximum widthdimension of the first anchor element is larger than the maximum widthdimension of the second anchor element in this aspect of the invention.The first anchor element is configured to be positioned inside the heartchamber and the second anchor element is configured to be positionedoutside the heart chamber with heart tissue held in the tissue receivingspace therebetween. As with the other devices/systems of this invention,this device may be installed in a patient through any suitable type ofsurgical procedure.

In another aspect of the invention, the device as generally describedimmediately above is implemented in a catheter based system. In thisaspect, the inflow cannula is more specifically a blood inflow catheterand the inflow catheter is configured to be directed into the venoussystem of the patient. The inflow catheter may be received by thedelivery catheter for purposes of establishing the blood inflow conduitin a minimally invasive manner.

In another aspect of the invention, the devices and systems of thepresent invention may further include a blood pump having an inlet andan outlet. The outlet is adapted for connection to a remote location inthe circulatory system of the patient via an outflow cannula or catheterand the inlet is adapted for connection to the inflow cannula.

In another aspect, the invention provides a method of establishing bloodflow from a chamber in a heart of a patient to a remote location forproviding supplemental blood flow from the heart. The method maycomprise inserting at least a portion of a distal end portion of aninflow cannula into the chamber of the heart. The distal end portionincludes first and second anchor elements each having a maximum widthdimension in a direction perpendicular to a lengthwise axis of theinflow cannula, and the first anchor element has a larger maximum widthdimension than the second anchor element. The method further comprisesplacing the first anchor element inside the chamber and against aninside surface of tissue defining the chamber, and placing the secondanchor element outside the chamber and against an outside surface of thetissue defining the chamber.

In another method performed in accordance with the inventive aspects, adistal end portion of an inflow cannula is inserted into a chamber ofthe heart and includes first and second anchor elements with the firstanchor element being located more distally than the second anchorelement, and with a tissue receiving space located between the first andsecond anchor elements. This method further comprises pulling the moreproximally located second anchor element out of the chamber. The moreproximally located second anchor element is engaged against an outsidesurface of tissue defining the chamber, while the first anchor elementis left inside the chamber to engage an inside surface of the chambersuch that the tissue is retained in the tissue receiving space and thecannula is in fluid communication with the chamber. If needed, variousmanners of further securing the tissue between the anchor elements maybe used. One manner may be the use of one or more purse string typesuture connections.

Various additional features and aspects of the embodiments and scope ofthe invention will be more readily appreciated upon review of thefollowing detailed description of the illustrative embodiments taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. IA is a schematic representation of chest anatomy, and illustratesone example of a pathway in the venous system used to access a patient'sheart.

FIG. IA-I is similar to FIG. IA, but illustrates another representativeand illustrative cannula or catheter pathway.

FIG. IB is an enlarged view of the chest anatomy, including the heart,and illustrates an initial step in establishing a pathway to the leftatrial chamber or left atrium of the heart.

FIG. IC illustrates an enlarged view of the heart and the catheterdevices used during the initial portions of the procedure.

FIG. I D is a view similar to FIG. IC, but illustrating a subsequentportion of the procedure.

FIG. I E is a view similar to FIG. I D, but illustrating a subsequentportion of the procedure.

FIGS. 1F-I H are views similar to FIGS. IC-IE, but illustrate subsequentprocedural steps involved with anchoring a blood inflow catheter to awall of the left atrium.

FIG. I1 is a view similar to FIG. 1B, but illustrates a step ofattaching a supplemental blood flow pump to proximal ends of the inflowand outflow catheters.

FIG. IJ is a view similar to FIG. I1, but illustrates the fullyimplanted system with the supplemental blood flow pump implantedsuperficially in a pacemaker pocket location.

FIG. 2 is a view similar to FIG. IH, but illustrating anotheralternative embodiment of the anchoring system and method of anchoringthe inflow catheter to the heart tissue.

FIG. 3A is a schematic representation of chest anatomy, and illustratesan example of another pathway, exterior to the venous system, used toaccess a patient's heart and implant a circulatory assist system inaccordance with another embodiment of the invention.

FIG. 3B is an enlarged view of the heart illustrating a location atwhich an incision may be made to expose an access location to theinterior of the heart.

FIG. 3C is a view similar to FIG. 3B, but illustrating the accesslocation exposed and generally showing an inflow cannula being directedtoward the access location.

FIG. 3D is an enlarged view of the access location or area of the heartillustrating two purse string sutures applied around a small incisionfor receiving the distal end or tip portion of the inflow cannula.

FIG. 3E is an enlarged view similar to FIG. 3D, but illustrating thedistal end portion of the inflow cannula completely inserted into theleft atrium of the heart through the incision.

FIG. 3F is a view similar to FIG. 3E, but illustrating the distal endportion of the inflow cannula partially pulled back and the purse stringsutures tightened.

FIGS. 4A and 4B are respective cross sectional views of the accesslocation with the inflow cannula distal portion properly placed andrespectively showing loose and tightened purse string sutures toillustrating the gathering of tissue between the cannula anchorelements.

FIG. 5 is a longitudinal cross sectional view of the inflow cannula.

DETAILED DESCRIPTION

FIG. IA illustrates one of many possible general configurations of ablood circulation assist system 10 implanted in accordance with theinventive aspects. Devices and systems configured in accordance with theteachings herein may be implanted in any suitable surgical manner,including but not limited to those discussed generally herein. FIG. IAshows the system 10 implanted in a transvenous endoluminal manner and,in particular, illustrates an inflow cannula 12 passing through thevenous system into the left atrium 14 of the heart 15 via the superiorvena cava 16 and subclavian vein 18. Because cannula 12 passes throughthe venous system, it is more particularly referred to herein as acatheter 12. The inflow catheter 12 exits at a site near the clavical ofthe patient 20. The distal end 12 a of the catheter 12 is positionedacross the interatrial septum 30 generally at the location of the fossaovalis such that the distal tip 12 a of the catheter 12 is within theleft atrium 14. Access may be made, for example, into any portion withinthe left side of the heart (e.g., the left atrium and/or left ventricle)to access oxygenated blood. The proximal end 12 b of the catheter 12 iscoupled to the inlet 32 of a blood pump 34. As further shown, anysuitable blood pump 34 may be used, including those described in U.S.Pat. Nos. 6,176,848; 16,862; 6,942,611; and 3,623,475 or DE 10 2004 019721 0.0. An outflow catheter 36 is connected between the outlet 38 ofthe pump 34 and an artery, such as the superficial axillary artery 40.Blood flow therefore travels in the direction of the arrows 42 from theleft atrium 14, through the pump 34, and into the patient's arterialsystem through the outflow catheter 36.

FIG. IA-I illustrates an alternative system configuration in which thetransvenous endoluminal implantation is performed via the jugular vein50. The inflow catheter 12 is brought from the jugular venous exit site52 along a subcutaneous tunnel formed from the pectoral pocket where thepump 34 is situated. While the system implantation configurations shownin FIGS. 1A and 1A-I are representative and desirable, it will beappreciated that many other implantation configurations and schemes maybe implemented depending on, for example, the needs of any particularpatient or desires of the surgeon.

FIGS. IB-I D illustrate in a sequential fashion the technique andcomponents used to perform a transeptal puncture into the left atrium14. For this application, the procedure may start from a subclavicularpectoral cut down 60 similar to that used for implantation of apacemaker. More specifically, FIG. 1B illustrates a transceptal systemincluding a sheath or delivery catheter 62 and a dilator device 64received in the delivery catheter 62. In this method, a needle (notshown) may be initially used to puncture the interatrial septum 30generally at the location of the fossa ovalis. This needle may then beexchanged for a guidewire 66 that is directed into the left atrium 14through the dilator device 64. FIG. IC illustrates the step of advancingthe dilator 64 across the interatrial septum 30 over the guidewire 66.The guidewire 66 is typically looped within the left atrium 14 to helpavoid any trauma to the heart tissue by the distal tip 66 a of theguidewire 66. FIG. I D illustrates the subsequent steps of advancing thetransceptal sheath or delivery catheter 62 across the septum 30 (i.e.,the tissue structure between the atrial chambers) and then retraction ofthe dilator 64 as illustrated by the arrow 70. The dilator 64 iscompletely removed leaving behind the sheath or delivery catheter 62with the distal tip 62 a located in the left atrium 14 and the guidewire66 for use during the next step of the procedure to deliver the inflowcatheter 12.

As shown in FIG. I E, the inflow catheter 12, which is the pump inflowcatheter of the system, may be introduced over the guidewire 66 andthrough the transceptal delivery catheter or sheath 62. The inflowcatheter 12 includes first and second anchor elements 80, 82 fixedthereto with the first anchor element 80 being located more distally onthe inflow catheter 12 than the second anchor element 82. In thisconfiguration, the anchor elements 80, 82 may be retained in a compactstate during delivery through the delivery catheter or sheath 62 and maybe expanded either selectively or automatically as they emerge from thedelivery catheter 62 during a subsequent step or steps.

FIG. I F illustrates the inflow catheter 12 is advanced until the mostdistal anchor element 80, that is, the first anchor element, is deployedwithin the left atrium 14 from the distal tip 62 a of the deliverycatheter 62. In this aspect, the first or distal anchor element 80 mayautomatically expand due to an expanding mechanism associated therewithor due to the characteristics of the material forming the anchor element80 itself as the anchor element 80 emerges from the delivery catheter62. Alternatively, a mechanism may be implemented for operation by thesurgeon to selectively expand one or both anchor elements 80, 82 asdesired during the procedure. As shown in FIG. IG, both anchor elements80, 82 may be deployed within the left atrium 14 as the inflow catheter12 is pushed out from the distal tip 62 a of the delivery catheter orsheath 62. Then, as indicated by the arrow 90 in FIG. IG, the inflowcatheter 12 is pulled proximally until the second anchor element 82 ispulled through the aperture 92 created in the interatrial septum 30 andresides against the outside surface (relative to the left atrialchamber) of the interatrial septum 30 as shown in FIG. IH. For purposesof assisting transfer of the second or proximal anchor element 82 acrossthe interatrial wall or septum 30 and providing perceptible feedback tothe surgeon, the second anchor element 82 may be formed with a smallermaximum width dimension than the first anchor element 80. For example,anchor element 80 may have an expanded diameter of 14 mm while element82 has an expanded diameter of 12 mm, in the case in which elements 80,82 are substantially circular discs. This ensures that the smalleranchor element 82 may noticeably pop through the aperture 92 in theinteratrial septum 30 leaving the larger anchor element 80 as a firmstop against the opposite side of the septum 30 within the left atrium14. The resulting connection will generally appear as shown in FIG. IH,although it will be appreciated that the anchor elements 80, 82themselves may be of various shapes, designs and configurations, and thedistal end 12 a of the inflow catheter 12 may or may not extend from thefirst anchor element 80 into the left atrium 14, as shown, but mayinstead be flush with the atrial side of the anchor element 80, orotherwise configured and shaped in any suitable manner.

To complete the system, an outflow catheter 36 is connected to thearterial system of the patient 20, such as illustrated. For example, theoutflow catheter 36 may be connected to the axillary artery 40 through asuitable surgical incision and attachment procedure which may involvethe use of suitable grafts and suturing 96. A supplemental blood flowpump 34, having an inlet 32 and an outlet 38 is coupled to the inflowand outflow catheters 12, 36. The inflow and/or outflow catheters 12, 36may first be cut to a suitable length by an appropriate sterilizedcutting tool 98 such that the system may be more easily implanted into,for example, a pectoral pacemaker pocket without kinking of catheters12, 36 as illustrated in FIG. IJ.

With reference to FIG. 2, like reference numerals indicate like elementsas described above. FIG. 2 illustrates an alternative anchoring methodin which the first and second anchor elements 80, 82 may reside onopposite sides of the tissue in a compact state, as shown, and then beselectively enlarged to anchor against and seal against the tissuewhich, in this example, is again the interatrial septum 30. As anotheralternative, the first anchor element 80 which resides in the leftatrium 14 (or other location in the left side of the heart) may beexpanded and seated against the inside surface of the atrium 14 as thesecond anchor element 82 is pulled back through the aperture 92 in itscompact state. The second anchor element 82 may then be expanded againstthe outside surface of the septum 30 (relative to the left atrialchamber 14). In this embodiment, as with the previous embodiment, theanchor elements 80, 82 may or may not be differently sized.

As mentioned above, the anchor elements 80, 82 may comprise any suitableconfiguration and may involve any suitable deployment method. Onedesirable shape is a disc-shaped element that acts as a flange extendingaround the outside of the blood inflow cannula 12 and capable of forminga fluid tight seal against the heart tissue. The material of the anchorelements 80, 82 may be, for example, a pliable and/or resilient materialsuch as surgical grade silicone. Alternatively, any other material(s)may be used. For example, materials may be used that promote ingrowth oftissue or that are covered by a material that promotes ingrowth oftissue. The anchor elements may be selfexpandable when removed from thedelivery catheter 62 or may be expanded by any suitable mechanismoperated by the surgeon. Other restraining members aside from thedelivery catheter 62 may be used as well to initially restrain theanchor elements 80, 82 in compact states during delivery to theattachment or anchoring site and optionally during initial portions ofthe anchoring procedure.

FIG. 3A illustrating a fully implanted circulatory assist system 100 inaccordance with another embodiment. Again, like numerals in the drawingsdescribed below represent like elements as previously described.Specifically, this system 100 comprises an inflow cannula 102, a bloodpump 104, and an outflow cannula 106. The outflow cannula 106 may beconnected to a superficial artery, such as the axillary artery 40 aspreviously described through the use of grafts (not shown) or in othersuitable manners. The inflow cannula 102 is attached directly to anexterior wall of the heart 15 on the left side, such as to the leftatrial wall 14 a, as shown. The inflow cannula 102, instead of beingdirected through the patient's venous system, is instead directed tothis exterior area of the heart 15 through any desired surgicalapproach, such as one of the approaches generally discussed below. Onceimplanted, the operation of the system 100 is similar to that describedabove in terms of drawing oxygenated blood from the left side of theheart 15 into the inflow cannula 102, through the pump 104, and out tothe arterial system via the outflow cannula 106.

More specifically referring to FIGS. 3B-3F, one illustrative procedurefor connecting the inflow cannula 102 is shown. In this regard, anaccess location 110 such as the so-called Waterson's groove is exposedor otherwise accessed during a surgical procedure. An incision may bemade with a scalpel 112 to expose the access location further. As shownin FIG. 3C, a small incision 120 is made to access the interior of theleft atrium 14 so as to allow for the insertion of the distal endportion 102 a of the inflow cannula 102. The distal end portion 102 a ofthe inflow cannula 102 includes distal and proximal anchor elements 122,124 similar to those previously described, however, other designs andconfigurations may be used instead. As shown in FIG. 3D, one or morepurse string sutures 130, 132 may be secured around the incision 120 inpreparation for the insertion of the cannula 102, or after the insertionof the cannula 102. The inflow cannula 102 may be inserted through theincision 120 such that both the distal and proximal anchor elements 122,124 are within the left atrium 14 as shown in FIG. 3E. Then, as shown inFIG. 3F, the inflow cannula 102 is withdrawn slightly proximally (towardthe surgeon) to position the proximal anchor element 124 outside theleft atrium 14 but leaving the distal anchor element 122 within the leftatrium 14. At this time, the purse string suture or sutures 130, 132 maybe tightened and tied off to fully secure the tissue 140 between thedistal and proximal anchor elements 122, 124 to provide a fluid tight orat least substantially fluid tight seal. It will be appreciated that anyother aspects of the previously described embodiment may be used in thisembodiment as well, such as the use of various materials includingsurgical grade silicone for the inflow cannula 102 and anchor elements122, 124, with or without tissue ingrowth material to further aide inproviding a leak tight connection to the left atrial chamber.

As further shown in FIGS. 4A and 4B, the purse string suture or sutures130, 132 may be tightened to a degree that is adequate to provide a leaktight seal. In this regard, the tightened tissue 140 should at leastsubstantially fill or gather within the gap between the distal andproximal anchor elements 122, 124 as schematically shown in FIG. 4B. Ifadditional gathering of tissue 140 is necessary, additional tissue 140may be gathered with one or more additional purse string sutures.

FIG. 5 illustrates the inflow cannula 102 in greater detail. In thisembodiment, the cannula 102 may be approximately 10 mm in diameter, withthe proximal anchor element 124 being 12 mm in diameter and the distalanchor element 122 being 14 mm in diameter. The tip dimension dlextending outwardly from the distal anchor element 122 is approximately2 mm, while the thicknesses ti, t2 along the longitudinal axis of thecannula 102 of anchor elements 122, 124 are each approximately 2.5 mm.The distance d2 between the distal and proximal anchor elements 122, 124is approximately 4 mm. It will be appreciated that these dimensions arerepresentative and illustrative in nature and may be changed accordingto the needs of any given case or patient. The inflow cannula 102, whichmay be constructed from surgical grade silicone, may also includereinforcements in the form of stainless steel or Nitinol coils 150. Itis desirable to have the inflow cannula 102 as flexible as possible, butstill of a design that prevents kinking. In view of the flexibility ofthe cannula 102, it may be necessary to provide stiffness to at leastthe distal end portion 102 a during insertion through the wall of theheart at access location 110 (or any other desired location). Thisstiffness may be provided only temporarily during the insertionprocedure. For example, a trocar (not shown) may be inserted temporarilythrough the proximal end 102 b of cannula 102 and into the distal endportion 102 a while inserting the cannula 102 into the heart 15 asdescribed herein. To retain the distal end of the trocar in the distalend 102 a of the cannula 102, there may be a balloon-like or otherexpandable element associated with the trocar that engages the interiorof the distal end 102 a during the cannula insertion process. After thecannula 102 is properly positioned as described herein, the trocar couldbe removed and the remainder of the implantation process, such asconnection of the pump 104 and outflow cannula 106 could take place. Asimilar process may be used during a catheterization procedure asdescribed herein.

Below, and as representative and nonlimiting examples, various surgicalapproaches are more fully described.

Surgical Open Sternotomv—This approach allows full access to the heart,especially the left atrium, and allows access to several differentlocations where a blood inflow cannula might be attached to the heart.However, due to the highly invasive nature of this approach, lessinvasive implantation approaches may be more desirable to a surgeon.

Surgical Open Thoracotomy—In this surgical approach, a relativelysuperior and caudal thoracotomy access is used to deliver the bloodinflow cannula to the left atrium where it is anchored at a location onthe roof of the atrium. This location on the atrium has specific benefitbecause the wall of the atrium is smooth and relatively large at thislocation, isolating the cannula tip from other structures within theatrium.

In another suitable surgical method, a relatively lateral thoracotomyaccess is used to deliver the blood inflow cannula to the left atriumwhere it is anchored at a location on the postero-medial wall near theinteratrial septum. This location is often called “Waterson's groove” asdiscussed above and is a common location to make a left atriotomy whenperforming mitral valve repair surgery. Waterson's groove is accessedsurgically by dissecting the left atrium away from the right atrium atthis posterior aspect, between the superior vena cava and the leftpulmonary veins.

Thoracoscopic Surgery—In this surgical method, the blood inflow cannulamay be implanted in a similar location as described above in that atubular trocar may be used to access the intra-thoracic location(Waterson's groove, for example) where the cannula would be anchoredthrough the heart wall. In this minimally or less invasive surgicalmethod, the entire operation is performed through these relatively smalltubular trocars thereby minimizing the size of the opening in thepatient's chest. Typically, additional small holes are made to delivertrocars used in conjunction with the main delivery trocar to allowplacement of an endoscopic camera and specialized surgical tools forgrasping, cutting, suturing, cauterizing, or performing other operationson tissue. Through the main trocar, the cannula can be delivered to thesame location as in the open surgical technique (i.e. Waterson's groove)but with less invasive access across the chest wall.

Transluminal—This method of implantation can, for example, involvedirecting the blood inflow cannula from the heart to the superficialremote pump location via a transluminal route. This transluminal routemay involve passing the cannula via the axillary and/or subclavian vein,through the superior vena cava into the left atrium and then anchoringthe cannula into the left atrium by passing it through the intra-atrialseptum, such as through the fossa ovalis. Alternatively, the cannulamight enter/exit the venous vasculature at the jugular vein. The cannulaproximal end may be routed to the superficial pectoral pump location bybeing tunneled under the skin or chest musculature.

Over-the-Wire (Seldinger) Technique—A method for implanting the cannula,whether in surgical or transluminal approaches, is to utilize a lowprofile and simple “over the wire” approach often called the Seldingertechnique. The Seldinger technique for percutaneously placing a catheterinto the lumen of a blood vessel involves inserting a needle into thevessel across its wall, and then following with a guide wire through theneedle. Once the guide wire is placed across the skin into the vessellumen, the needle can be removed and then a suitable catheter placedover the wire into the vessel lumen. This technique minimizes trauma tothe vessel wall, as often the hole across the vessel wall is gentlyexpanded or dilated by the catheter being introduced. Another keyadvantage of the technique is that blood loss is minimized becausecontrol of the hole size around whatever is inserted is maintained. Asan example, the transluminal cannula could be introduced into thejugular or subclavian vein after access to the vessel is obtained usingthe percutaneous Seldinger technique, where the cannula would be adaptedto be introduced into the vessel over the guide wire. Such adaptationswould include an obturator or dilator within the inner lumen of thecannula and thereby providing support and lumen size matching tofacilitate dilation and blood maintenance through the puncture site.Once the cannula is introduced via the percutaneous puncture site, asurgical tunnel from the pectoral pocket location of the pump may bemade up to the subcutaneous location of the veinotomy, where the exposedend of the cannula would be secured and pulled through the tunnel to thepump pocket.

Alternatively, a variation of the Seldinger technique might be utilizedin the various surgical implantation approaches described above, wherethe cannula system would be specifically adapted to facilitate thisimplantation technique. Although the Seldinger technique is mostcommonly associated with percutaneous access to blood vessels, anadapted version of the technique utilizing a specifically adaptedcannula introduction system is a highly preferred approach to surgicalimplantation where direct access to the heart itself is utilized. Here,for example, an atriotomy could be made by inserting a needle across theheart wall and a guide wire then placed therethrough. After removal ofthe needle, with bleeding controlled and minimal, the cannula systemwith specialized introduction obturator within can be introduced overthe wire thereby maintaining many of the advantages of the so-calledSeldinger technique even in a surgical approach.

While the present invention has been illustrated by a description ofvarious illustrative embodiments and while these embodiments have beendescribed in some detail, it is not the intention of the Applicants torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. The various features of the invention may beused alone or any combinations depending on the needs and preferences ofthe user. However, the invention itself should only be defined by theappended claims.

What is claimed is:
 1. A blood circulation assist device comprising: aninflow cannula including a proximal end portion and a distal end portionopposite the proximal end portion, the distal end portion and theproximal end portion defining a longitudinal axis extendingtherebetween; a first anchor element at the distal end portion, thefirst anchor element having a first diameter and a thickness along thelongitudinal axis; and a second anchor element disposed distallyrelative to the first anchor element at the distal end portion, thesecond anchor element having a second diameter larger than the firstdiameter and the thickness of the first anchor element.
 2. The bloodcirculation assist device of claim 1, wherein the first anchor elementand the second anchor element define a distance therebetween, thedistance being greater than the thickness.
 3. The blood circulationassist device of claim 2, wherein the distance between the first anchorelement and the second anchor element is approximately 4 mm.
 4. Theblood circulation assist device of claim 1, wherein the first diameterof the first anchor element is approximately 12 mm and the seconddiameter of the second anchor element is approximately 14 mm.
 5. Theblood circulation assist device of claim 1, wherein the thickness isapproximately 2.5 mm.
 6. The blood circulation assist device of claim 1,wherein the first anchor element and the second anchor element are eachan annular disc extending radially outward from the inflow cannula. 7.The blood circulation assist device of claim 1, wherein the firstdiameter of the first anchor element and the second diameter of thesecond anchor element are each a maximum width dimension.
 8. The bloodcirculation assist device of claim 1, wherein the inflow cannulaincludes a plurality of coils extending along the longitudinal axis. 9.The blood circulation assist device of claim 1, wherein the first anchorelement and the second anchor element are transverse with respect to thelongitudinal axis.
 10. The blood circulation assist device of claim 1,wherein the first anchor element and the second anchor element areconfigured to provide a fluid-tight seal between a portion of a hearttissue.
 11. A blood circulation assist device comprising: an inflowcannula including a distal end portion and a proximal end portionopposite the distal end portion, the distal end portion having a firstanchor element and a second anchor element being distal relative to thefirst anchor element, the first anchor element and the second anchorelement each surrounding the distal end portion and defining atissue-receiving space therebetween, the first anchor element defining afirst diameter and the second anchor element defining a second diameterlarger than the first diameter.
 12. The blood circulation assist deviceof claim 11, wherein the first anchor element includes a first thicknessand the second anchor element includes a second thickness approximatelyequal to the first thickness.
 13. The blood circulation assist device ofclaim 12, wherein the tissue-receiving space defines a distance, thedistance being greater than the first thickness of the first anchorelement and the second thickness of the second anchor element.
 14. Theblood circulation assist device of claim 12, wherein the distal endportion and the proximal end portion define a longitudinal axisextending therebetween, and the first thickness and the second thicknessextend along the longitudinal axis.
 15. The blood circulation assistdevice of claim 14, wherein the inflow cannula includes a plurality ofcoils extending along the longitudinal axis.
 16. The blood circulationassist device of claim 11, wherein the first anchor element and thesecond anchor element are annular discs.
 17. The blood circulationassist device of claim 11, wherein the first anchor element and thesecond anchor element are configured to form a fluid tight seal withinthe tissue-receiving space.